Four years ago, my daughter Olivia was diagnosed with a rare and aggressive genetic disorder that attacks the brain and nervous system. She was rapidly losing the ability to walk and talk, and doctors told us that the disease was progressive, meaning Olivia's condition would continue to worsen and she would eventually need hospice care. She was not yet 2 years old. A few months later, our youngest daughter, Keira, was diagnosed with the same genetic disorder – metachromatic leukodystrophy (MLD).